5 Answers
5

If you want this HTML-based solution, you can always cheat a bit. You can have it launch an index.html, which uses javascript to find out what OS the system is using, and redirect to mac/index.html or win/index.html

Partition the USB stick - half HFS+ for the Mac and half NTFS.
This SHOULD be readable by both platforms - then you can put on anything you like.
A PC will see the NTFS partition, but not HFS+, the Mac will see both but only write to the HFS+.

That will give you a seamless data solution, even though FAT32 is far from the best file system. Unfortunately, with improved file systems like NTFS or those supported by Macintosh, have incomplete, limited, or no support in the "other" operating system.

If you wanted something more specific, you'd better revise the question.